### About the Number 42 (forty-two)

MathBabbler was BABbling about the number 1776 and discovered that `sqrt(1776)` rounded to the nearest whole number is 42.

The number 42 is "The Answer to the Ultimate Question of Life, the Universe, and Everything, according to Douglas Adams' series The Hitchhiker's Guide to the Galaxy."

The query "the answer to life, the universe, and everything" into Google (without the quote marks), produces the answer 42 by the Google calculator. [was true on 4 July 2007]

```   42 in binary is 101010 (odious)
42 days is 10! seconds
42 is a Harshad number (4 + 2 is a factor of 42)
42 is unhappy
42 is abundant (sum_proper_divisors(42) = 54)
log(42) = 1.62 (Phi rounded to the nearest hundredth)
floor(sqrt(1776)) = 42
```
##### Exercises
1. List the prime factors for number 42.

2. No or Yes: The 1st digit of 42 raised to the power of the 2nd digit of 42 equals the 2nd digit of 42 raised the power of the 1st digit of 42.

3. 10! = 3.6288 * 10^(n/7) when n = ______

4. No or Yes: 42 is a factor of 420.

##### Update::2008.01.25

Super Bowl XLII is being played in Glendale, Arizona, during February 2008. For some reason the Super Bowl numbering is done using Roman numerals. It turns out XLII is 42.

MathBabbler inserted this update because he didn't know how to convert Roman numerals into decimal numbers and he has now learned how to do it (to an extent). He alerted his CSC100 students that they might get an opportunity to write a Roman numeral-decimal number converter program.

```   XLII = 42                X=10  L=50  I=1
X is less than L and since X proceeds L,
X is subtracted from L and two I's are added
(i.e. 50 - 10 + 1 + 1 = 42)
```

The date of Super Bowl XLII was II/III/MMVIII.

The last time a Super Bowl was played in Arizona was Super Bowl XXX and it was played on I/XXVIII/MCMXCVI.

##### Update::2009.08.16

MathBabbler learned from the Arizona Republic that Elvis Presley died at the age of `42` on 16 August 1977.

The MBNA (MathBabbler Number Analyst) changed a lot between the time this nBAB was created (2007.07.04) and this date of this update (2009.08.16).

```   MathBabbler Number Analyst (MBNA) output:
=========================================
42 is a natural, whole, integer
42 is even
42 proper divisors are: 1,2,3,6,7,14,21,
42 is abundant (sum of divisors is 54)
42 is unhappy
42 is a Harshad number
42 is not prime
42 has the prime factors: 2*3*7 (sum=12)
42 is sphenic (had 3 unique prime factors)
42 sum of prime factors is: 12
42 is undulating
42 is pronic (oblong)
42 is ThurmNumber
42 in octal is 052
42 in hexadecimal is 0x2a
42 in binary is 101010 (is odious)
42 nearest square numbers: -6...7 (36...49 )
sqrt(42) = 6.48074
ln(42) = 3.73767
log(42) = 1.62325
42 reciprocal is .02380952380952380952380952380952
42! is 1.40501e+51
42 is 13.369 Pi years
42 is 2 score and 2 years
42 written as a Roman numeral is XLII
```

`42` is the smallest ThurmNumber. [A ThurmNumber is a number that when written in score plus number format has a prime score and a prime plus number.]

MathBabbler posted this update at the age of 52, which in octal (i.e. base-8), is `42`. In addition, 52 is the average of `4212` and `4213` (i.e. 50 and 54, respectively).

`42` in hexadecimal (base-16) is repdigit 66 in decimal (base-10) and `42` in base-5 is base-10 repdigit 22.

`log(42)` (1.62325) rounded to the nearest hundredth equals Phi (i.e. the golden ratio) rounded to the nearest hundredth.

##### Update::2009.11.27

BBC.co.uk::H2G2::42

Creator: Gerald Thurman [gthurman@gmail.com]
Created: 04 July 2007 